The present invention relates to zeolite-activated guano phosphates and to methods for producing the same.
In recent years, soils around the world have been acidified and hardened because of the use of chemical fertilizers, thereby causing the loss of nutriment in the soils and lowering the productivity of plants.
Conventional chemical phosphate fertilizers are produced from phosphate-containing minerals which are usually hard and contain 4% to 6% fluorine by weight. The method to produce these fertilizers is to treat the phosphate-containing minerals with sulfuric acid and/or nitric acid, thereby causing the decomposition of the minerals therein. The reaction of the conventional process for producing phosphate fertilizers is as follows: EQU Ca.sub.3 (PO.sub.4).sub.2 +H.sub.2 SO.sub.4 +6H.sub.2 O.fwdarw.2(CaHPO.sub.4.2H.sub.2 O)+CaSO.sub.4.2H.sub.2 O
wherein the accompanying CaSO.sub.4 will acidify and harden soil. Since the previous reaction is a chemical reaction, the CaSO.sub.4 will be inseparable with the CaHPO.sub.4.2H.sub.2 O. Thus, the molecular weight percentage of the phosphoric anhydride is: ##EQU1## The molecular weight percentage of the phosphoric anhydride in Ca.sub.3 (PO.sub.4).sub.2 of the phosphate-containing minerals is: ##EQU2## Thus, the lowest possible weight percentage of the phosphoric anhydride in the phosphate fertilizers produced from the phosphate-containing minerals is: ##EQU3## This content is essentially the same as the standard content of phosphoric anhydride required in the phosphate fertilizers. But in general, the chemical reaction being carried out rarely reaches 100%. Thus, to maintain the proportion of the phosphoric anhydride in the phosphorus-containing fertilizers at 18% by weight, it is necessary to select phosphate-containing minerals that contain more than 34% phosphorus by weight before proceeding with chemical treatments, thereby causing an increase in cost.
It is the purpose of this present invention, therefore, to mitigate and/or obviate the abovementioned drawbacks in the manner set forth in the detailed description of the preferred embodiment.